UVA photoprotective cosmetic/dermatological compositions comprising iron chelating agents

ABSTRACT

Topically applicable UVA photoprotective cosmetic/dermatological compositions comprise an effective photoprotecting amount of at least one UVA screening agent substituted by at least one optionally neutralized sulfo functional group, and an effective UVA photoprotecting-enhancing amount of at least one otherwise non-UVA photoprotecting iron chelating agent, thereby imparting a synergistic protection factor (PF) effect thereto, in a cosmetically/dermatologically acceptable topical vehicle, carrier or diluent therefor.

This application is a Divisional of application Ser. No. 08/685,913,filed on Jul. 22, 1996, now U.S. Pat. No. 5,776,472.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a novel topically applicablecosmetic/dermatological compositions for the photoprotection of humanskin and/or hair. The subject compositions prevent and/or to combataging of the skin, especially due to ultraviolet A radiation, andprotect the skin and/or the hair against such radiation and against freeradicals. The compositions of the invention are formulated, for example,as smooth white creams or as gels which may be topically applied to thehuman face, body and/or legs and to the hands and scalp.

2. Description of the Prior Art

It is known to this art that, over time, various signs which are verycharacteristic of aging appear on the skin, reflected in particular in amodification of the cutaneous structure and functions.

The principal clinical signs of cutaneous aging are, notably, theappearance of deep wrinkles and fine lines, which increase with age. Inparticular, disruption of the "grain" of the skin is observed, namely,its microrelief is less uniform and is anisotropic in nature.

Moreover, the skin complexion is generally modified; it appears palerand yellower, which appears to be due essentially to disruption of themicrocirculation (less haemoglobin in the dermal papillae). Furthermore,many colored and/or darker blemishes appear on the skin surface, andmore especially on the hands, imparting heterogeneity to the skin. Ingeneral, these blemishes are due to considerable production of melaninin the skin epidermis and/or dermis. In certain instances, theseblemishes may become cancerous. Thus, it is increasingly sought toreduce these blemishes, or even to eliminate same. Too, diffuseirritations, and sometimes telangiectasia, may occur on certain areas ofthe skin.

Another clinical indication of aging is the dry and rough appearance ofthe skin, which is essentially due to a more considerable descuamation;by scattering light rays, these squama also contribute to the somewhatgrey appearance of the complexion.

Finally, a loss of firmness and of tonicity of the skin is observedwhich, as in the case of wrinkles and fine lines, is at least partlyexplained by a dermal and epidermal atrophy and flattening out of thedermoepidermal formation; the skin is thinner and more flaccid, and thethickness of the epidermis decreases.

It is thus observed that the clinical signs of cutaneous aging resultessentially from a dysfunction of the principal biological mechanismstaking place in the skin.

Such aging can be physiological in nature but also photoinduced, namely,due to repeated exposure of the skin to sunlight, and especially toultraviolet A irradiation. The action of this light on the constituentsof the skin and on the sebum secreted by the skin results, inparticular, in the formation of oxygenated free radicals. These freeradicals inflict considerable damage, especially in cell membranes(permeability of the membranes), cell nuclei (mutation by action on RNAor DNA) and tissues (necrosis and degeneration); it is thus necessary toprotect the skin against these free radicals.

Hence, serious need continues to exist in this art for compositionscapable of preventing and/or combating the onset of aging and the signsof aging, such as wrinkles and fine lines, of preventing and/orcombating skin pigmentation blemishes, whatever their origin, and ofprotecting the skin, especially by suppression of the formation ofoxygenated free radicals.

One of the known means for effectively combating premature aging of theskin is to topically apply thereto a UVA screening agent which absorbsat wavelengths between 320 and 400 nm. This decreases the excessphotoinduced free radicals. However, such photoprotection is less thancomplete with the majority of compositions containing UVA screeningagents. Thus, upon repeated exposures, the residual amount of freeradicals, persisting despite the protection by the UVA screening agent,can induce, over the long term, photoactinic aging phenomena.

It has been proposed to increase the amounts of UVA screening agents,but it is not advisable to apply excessively large levels of screeningagents in cosmetic products for daily care. Indeed, with the majority ofscreening agents, a maximum protection factor is often attained which isvery difficult to improve by increasing the level of screening agents.In addition, it is necessary to take account of the fact that daily careproducts are more frequently used than other seasonal productscontaining screening agents, such as sunscreen products for example,which can result in cosmetic discomfort and problems of toxicity by thetopical route.

In order to more effectively combat photoactinic aging, it is thereforeadvantageous to employ means other than the use of large amounts of UVAscreening agent. In particular, it is possible to combine, with UVAscreening agents, molecules capable of blocking the chain reactions offree radicals before the final stages of degradation of the biologicalconstituents of the skin. These compounds are antioxidizing agentsand/or anti-free radicals.

It too is known that photoinduced free radicals arise principally frommolecular oxygen. Given that it is common in the body and that it isreadily able to accept electrons, the free radicals and the activatedoxygen species which derive therefrom are the most numerous participantsin radical reactions. The following are representative:

Singlet oxygen: non-radical, high oxidizing, very toxic and very rarebecause it has a very short lifetime. It is the product of theexcitation of molecular oxygen by light photons.

The superoxide radical anion: it is the product of the addition of anelectron to molecular oxygen. It can initiate the production of veryreactive free radicals, the hydroxyl radicals.

Hydrogen peroxide: non-radical but which can initiate the production ofhydroxyl radicals.

The hydroxyl radical: it is highly oxidizing, and therefore veryreactive, and the most toxic in respect of human cells.

Exemplary thereof are lipoperoxide radicals, which are species derivedfrom the oxidation of membrane lipids.

Extracellular iron is also representative, which, by reacting withhydrogen peroxide and the superoxide radical anion which haveaccumulated outside the cell, will promote the production of thehydroxyl radical.

SUMMARY OF THE INVENTION

In order to effectively combat oxygenated free radicals and thus tocombat photoaging, a unique combination of a UVA screening agent withone or more antioxidizing and/or antiradical molecules has nowunexpectedly and surprisingly been developed which exhibits asynergistic effect and especially a protection factor greater than thatof the screening agent alone, whereas these antioxidizing and/orantiradical molecules themselves exhibit no screening activity for UVAradiation.

Briefly, it has now surprisingly been found that, on combining one ormore iron chelating agents with one or more UVA photoprotective agents,the screening power of the latter is increased.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OFTHE INVENTION

More particularly according to the present invention, provided are novelcompositions for topical application, intended especially for preventingand/or combating aging of the skin and/or cutaneous blemishes and/orprotecting the skin and/or the hair against ultraviolet radiation and/oragainst free radicals, which exhibit an effectiveness which isconspicuously greater than that of the prior art.

In a preferred embodiment of the invention, the subject compositionscontain, in a medium (vehicle, carrier or diluent) acceptable fortopical application, at least one screening agent which absorbs at leastultraviolet A irradiation, including at least one optionally neutralizedsulfo functional group, and at least one iron chelator or chelatingagent which does not exhibit the property of screening such radiation,the screening agent and the chelator being present in an amount suchthat they synergistically act to impart to the composition a protectionfactor in respect of ultraviolet A radiation which is greater than thatof the screening agent alone.

The screening power of the subject compositions in the UVA range isrepresented by the protection factor, designated PF. The determinationof the screening power UVA is based on the technique for evaluation ofthe pigmentation induced by UVA (Persistant Pigment Darkening:PPD). Thistechnique is described by Chardon and al, Method for the UVA protectionassessment of sunscreens based on residual immediate pigment darkening,20th Annual Meeting of the American Society for Photobiology, Marcoisland, Fla. (USA) , Jun. 20-24, 1992.

The iron chelating agent or agents advantageously have an associationconstant with ferrous or ferric ions greater than 10², preferablygreater than 10⁶. Exemplory iron chelating agents include the salts ofethylenediaminetetramethylenephosphonic acid, and especially thepentasodium salts, and ethylenediaminetetraacetic acid. Alsorepresentative thereof are citric acid, tartaric acid, phytic acid andsalts thereof and dibenzyldithiocarbamate. They are formulated in aproportion of 0.001% to 5% and preferably of 0.1% to 2% of the totalweight of the composition.

The compositions of the invention preferably contain one or more otherantioxidizing and/or antiradical agents selected from among agents forcombating lipoperoxide radicals, compounds for regenerating oxidizedvitamin E, agents for combating the hydroxyl radical, agents forcombating singlet oxygen and agents for combating the superoxide radicalanion, and combinations thereof. These compounds are addvantageouslypresent in amounts ranging from 0.0001% to 5%.

The compositions of the invention contain one or more UVA screening orphotoprotecting agents in an amount which is effective for screeningsuch UVA radiation. In actual practice, these screening agents typicallyconstitute from 0.01 to 10%, preferably from 0.1% to 5%, of the totalweight of the composition. These screening agents are moleculescontaining one or more optionally neutralized sulfo functional groups ormolecules containing one or more sulfonate functional groups.

The bases used to neutralize one or more sulfo functional groups of theUVA screening agents are preferably organic bases, generally used in thecosmetics field, such as triethanolamine and ethylenediamine.

The UVA screening agents which may be used in the invention may belipophilic or, preferably, hydrophilic. exemplary such screening agentsinclude sulfo or sulfonate derivatives of benzophenone, such as2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, marketed by BASF underthe trademark Uvinul MS-40, and sulfo or sulfonate derivatives ofbenzylidenecamphor.

In particular, the benzylidenecamphor derivatives which may beformulated into the compositions of the invention have the followinggeneral formula (a): ##STR1## in which B represents --H or --SO₃ H;0≦p≦1 wherein B=--SO₃ H when p=0; 0≦n≦4; D represents one or more linearor branched chain alkyl or alkoxy radicals, which may be identical ordifferent when n≧2, having from about 1 to 18 carbon atoms, a halo atomor a hydroxyl radical; A, preferably in the meta or para position,represents either an --SO₃ H radical, or a radical: ##STR2## in which Yrepresents --H or --SO₃ H, or a radical: ##STR3## in which R₁₁ is ahydrogen atom, a linear or branched chain alkyl or alkoxy radical havingfrom about 1 to 6 carbon atoms or the --SO₃ H radical, R₁₁ being --SO₃ Hwhen B =--H; R₁₂ is a hydrogen atom or a linear or branched chain alkylor alkoxy radical having from about 1 to 6 carbon atoms; X is an oxygenor sulfur atom or a radical --NR--, wherein R is a hydrogen atom or alinear or branched chain alkyl radical having from about 1 to 6 carbonatoms, and in which at least one --SO₃ H functional group is optionallyneutralized.

Specific examples of compounds of formula (a) which are representativeof the compounds of formulae (I), (II) and (III) are set forth below:##STR4## in which Z, preferably in the para or meta position, is aradical: ##STR5## wherein Y is --H or --SO₃ H, which is optionallyneutralized; n is equal to 0 or is a number ranging from 1 to 4 (0≦n≦4);and R₁ is one or more linear or branched chain alkyl or alkoxy radicals,which may be identical or different, having from about 1 to 4 carbonatoms.

A particularly preferred compound of formula (I) is that correspondingto n=0, Z in the para position and Y=--SO₃ H:benzene-1,4-[di(3-methylidene-10-camphorsulfonic)] acid which is alsoreferred to (according to CTFA nomenclature, 5th Edition) asterephthalylidenedicamphorsulfonic acid. ##STR6## in which R₂ is ahydrogen atom or an --SO₃ H radical; R₃, R₄, R₅ and R₆, which may beidentical or different, are each a hydroxyl group, a linear or branchedchain alkyl radical having from about 1 to 4 carbon atoms, a linear orbranched chain alkenyl radical having from 2 to 4 carbon atoms, a linearor branched chain alkoxy radical having from 1 to 4 carbon atoms, alinear or branched chain alkenyloxy radical having from 2 to 4 carbonatoms, or a halo atom; furthermore, only one radical R₃ to R₆ may be an--SO₃ H radical, at least one of the radicals R₃ to R₆ denoting the--SO₃ H radical when R₂ is a hydrogen atom. One or more --SO₃ Hfunctional groups may also be neutralized.

Specific examples which are representative are the following compoundsof formula (II), in which:

R₄ is the --SO₃ H radical in the para position of benzylidenecamphor andR₂, R₃, R₅ and R₆ are each a hydrogen atom, i.e.,4'-sulfo-3-benzylidenecamphor;

R₃, R₄, R₅ and R₆ are each a hydrogen atom and R₂ is an --SO₃ H radical,i.e., 3-benzylidene-10-camphorsulfonic acid;

R₄ is a methyl radical in the para-position of benzylidenecamphor, R₅ isan --SO₃ H radical and R₂, R₃ and R₆ are each a hydrogen atom, i.e.,4'-methyl-3'-sulfo-3-benzylidenecamphor;

R₄ is a chlorine atom in the para-position of benzylidenecamphor, R₅ isan --SO₃ H radical and R₂, R₃ and R₆ are each a hydrogen atom, i.e.,4'-chloro-3'-sulfo-3-benzylidenecamphor;

R₄ is a methyl radical in the para-position of benzylidenecamphor, R₃,R₅ and R₆ are each a hydrogen atom and R₂ is an --SO₃ H radical, i.e.,4'-methyl-3-benzylidene-10-camphorsulfonic acid;

R₂ is an --SO₃ H radical, R₃ is a methyl radical, R₄ is a hydrogen atom,R₅ is a tert-butyl radical and R₆ is a hydroxyl radical, namely,3'-t-butyl-2'-hydroxy-5'-methyl-3-benzylidene-10-camphorsulfonic acid;

R₂ is an --SO₃ H radical, R₃ is a methoxy radical, R₄ is a hydrogenatom, R₅ is a tert-butyl radical and R₆ is a hydroxyl radical, i.e.,3'-t-butyl-2'-hydroxy-5'-methoxy-3-benzylidene)-10-camphorsulfonic acid;

R₂ is an --SO₃ H radical, R₃ and R₅ are each a tert-butyl radical, R₄ isa hydroxyl radical and R₆ is a hydrogen atom, i.e.,3',5'-di-tert-butyl-4'-hydroxy-3-benzylidene-10-camphorsulfonic acid;

R₄ is a para-methoxy radical, R₅ is --SO₃ H and the radicals R₂, R₃ andR₆ are each H, namely, 4'-methoxy-3'-sulfo-3-benzylidenecamphor;

R₂ is an --SO₃ H radical, R₃ and R₆ are each H or R₄ and R₅ togetherform a methylenedioxy radical, i.e., 3',4'-methylenedioxy-3-benzylidene-10-camphorsulphonic acid;

R₂ is an --SO₃ H radical, R₄ represents a methoxy radical and theradicals R₃, R₅ and R₆ represent H, namely,4'-methoxy-3-benzylidene-10-camphorsulfonic acid;

R₂ represents an --SO₃ H radical, R₄ and R₅ are each a methoxy radicaland the radicals R₃ and R₆ are each H, namely, 3',4'-dimethoxy-3-benzylidene-10-camphorsulfonic acid;

R₂ is an --SO₃ H radical, R₄ is an n-butoxy radical and the radicals R₃,R₅ and R₆ are each a hydrogen atom, i.e.,4'-n-butoxy-3-benzylidene-10-camphorsulfonic acid;

R₂ is an --SO₃ H radical, R₄ is an n-butoxy radical, R₅ is a methoxyradical and R₃ and R₆ are each a hydrogen atom, i.e.,4'-n-butoxy-3'-methoxy-3-benzylidene-10-camphorsulfonic acid. ##STR7##in which R₁₁ is a hydrogen atom, a linear or branched chain alkyl oralkoxy radical having from about 1 to 6 carbon atoms, or an --SO₃ Hradical, R₁₂ is a hydrogen atom or a linear or branched chain alkyl oralkoxy radical having from about 1 to 6 carbon atoms, R₁₃ is a hydrogenatom or an --SO₃ H radical, with the proviso that at least one of theradicals R₁ l and R₁₃ is an --SO₃ H radical, and X is an oxygen orsulfur atom or a group --NR--, wherein R is a hydrogen atom or a linearor branched chain alkyl radical having from about 1 to 6 carbon atoms.

One specific example of a compound of formula (III) which isparticularly representative is the compound in which X is an --NH--radical, R₁₁ is an --SO₃ H radical, and R₁₂ and R₁₃ are each a hydrogenatom, i.e., 2-[4-(camphormethylidene)phenyl]benzimidazole-5-sulfonicacid.

The compounds of structural formulae (I), (II) and (III) are describedin U.S. Pat. No. 4,585,597 and in FR-2,236,515, 2,282,426, 2,645,148,2,430,938 and 2,592,380.

Other benzylidenecamphor compounds of the invention include thecompounds of general formula (b): ##STR8## in which R₉ is a divalentradical --(CH₂)_(m) -- or --CH₂ --CHOH--CH₂ --, wherein m is an integerranging from 1 to 10 (1≦m≦10); R₁₀ is a hydrogen atom, an alkoxy radicalhaving from about 1 to 4 carbon atoms, or a divalent radical --O--bonded to the radical R₉ when the latter is also divalent; and Y and Y'are each a hydrogen atom or an --SO₃ H radical, at least one of theseradicals Y or Y' being other than hydrogen. In this instance also, the--SO₃ H functional group may be neutralized.

One specific example of a compound of formula (b) is that in which Y is--SO₃ H, Y' is --H, R₁₀ is H and R₉ is --CH₂ --CH₂ --, i.e.,ethylenebis[3-(4'-oxybenzylidene)-10-camphorsulfonic] acid.

It is possible to use one or more active agents for combatinglipoperoxide radicals in an amount preferably ranging from 0.05% to 5%and, preferably, from 0.2% to 3% of the total weight of the composition.These agents include, for example, vitamin E (or D,L-α-tocopherol) andderivatives thereof, or any other compound which is effective in vitroin the so-called β-carotene test or in the rancimat test, such asγ-orizanol, natural extracts, such as the OPCs of hawthorn, of pine orof grape, or extracts of gall apple or of rosemary.

The compositions of the invention advantageously contain at least oneUVA screening agent, such asbenzene-1,4-[di(3-methylidene-10-camphorsulfonic)] acid, one ironchelator, such as Dequest 2046, and one agent for combating lipoperoxideradicals, for example vitamin E.

The compositions of the invention may be formulated into allpharmaceutical dosage forms normally employed for topical application,such as solutions, aqueous or aqueous/alcoholic gels, oil-in-water orwater-in-oil emulsions, and more particularly droplets of oil dispersedby means of spherules in an aqueous phase. These spherules may bepolymeric nanoparticles such as nanospheres and nanocapsules or,preferably, may be lipid vesicles. The compositions of the invention maybe provided in the form of a cream, an ointment, a gel, a lotion or aserum.

The oils which may be included according to the invention are thosegenerally employed in the cosmetics/sunscreen arts. They may be plant,mineral or synthetic oils, and may optionally be silicone-containingand/or fluorinated oils.

The compositions of the invention may also contain hydrophilic orlipophilic adjuvants and additives such as gelling agents,preservatives, opacifying agents, emulsifying agents, co-emulsifyingagents, neutralizing agents, fragrances and dissolving agents orpeptizing agents thereof, colorants such as dyes and pigments, andfillers, as well as lipophilic or hydrophilic active agents other thaniron chelators and chemical screening agents which absorb in theultraviolet A. In particular, it is possible to add UVB screening agentsto the subject compositions, for the purpose of preventing sunburn andsunstroke upon exposure to sunlight.

The amounts of oil and of water are generally those coventional in thisart and depend on the pharmaceutical dosage form of the composition. Foran oil-in-water emulsion or a dispersion of oil in water by means oflipid spherules, the oil may constitute from 0.5% to 60%, preferablyfrom 2% to 40%, of the total weight of the composition.

Similarly, the adjuvants and additives are formulated in the usualamounts and may constitute, in total, from 0.1% to 20% by weight. Theamount of adjuvants and additives depends on their nature.

The compositions of the invention may be applied topically to allregions of the body and of the face, including the scalp, the legs andthe hands.

The present invention also features the use of the subject compositionsfor the cosmetic treatment of wrinkles and/or fine lines of the skin,induced via UVA irradiation, as well as for protecting, moisturizingand/or firming the skin.

Too, this invention features the use of the subject compositions forcombating photoinduced skin aging.

This invention also relates to the use of the subject compositions fordepigmenting the skin and/or cosmetically treating skin blemishesattributed to aging, these blemishes afflicting the face and/or thebody, including the hands and the scalp, as well as for formulation intoa cream suitable for the treatment of skin blemishes of pathologicalorigin.

The subject compositions are also useful for protecting the skin againstfree radicals.

Thus, the present invention features the cosmetic and/or dermatologicaltreatment of the skin, comprising topically applying the subjectcompositions thereto.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative. Insaid examples to follow, the constituents of the compositions areexpressed in % by weight.

EXAMPLE 1

Tests were carried out to demonstrate the advantages of the presentinvention. The objective of the tests was to evidence the ability of thecompositions of the invention to protect against free radicals.

The following composition (A) was prepared, by way of example: anoil-in-water emulsion containing a pentasodium salt ofethylenediaminetetramethylene-phosphonic acid (Dequest 2046 marketed byMonsanto) and benzene-1,4-[di(3-methylidene-10-camphorsulfonic)] acid.The composition (B), which was the same emulsion as the composition (A),but which contained only the UVA screening agent, was also prepared.

Surprisingly, the UVA protection factor (PF) of the composition (A) wasgreater than that of the screening agent alone, which indicates that thecomposition of the invention screened UVA radiation more efficientlythan the screening agent alone.

The values of the UVA protection factors of the compositions (A) and (B)were measured in vivo on 5 test subjects (PPD method).

The results were:

Composition (A)>Composition (B) for 80% of the subjects (15% increase).

The photoprotection in the UVA range of the composition (A) wastherefore notably greater than that of the composition (B) containingthe screening agent alone.

The following Examples 2-5 set forth specific embodiments ofcompositions according to the invention:

EXAMPLE 2

Water-in-oil cream for daily use on wrinkles:

    ______________________________________                                        Composition                                                                   ______________________________________                                        A.sub.1 :                                                                            (i)     Stearic acid       0.4%                                               (ii)    Polyethylene glycol stearate                                                                     3.5%                                                       (40 EO) (emulsifying agent)                                           (iii)   Glyceryl mono,di,  3.0%                                                       tripalmitostearate                                                            (emulsifying agent)                                                   (iv)    Isopropyl palmitate (oil)                                                                        7.0%                                               (v)     Hydrogenated isoparaffin                                                                         6.5%                                                       (6-8 mol of isobutylene)                                                      (oil)                                                          A.sub.2 :                                                                            (vi)    Cyclopentadimethylsiloxane (oil)                                                                 5.0%                                        B:     (vii)   Sterilized demineralized                                                                         for 100%                                                   water q.s.                                                            (viii)  Glycerol (moisturizing                                                                           3.0%                                                       agent)                                                                (ix)    Iron chelating agent                                                                             2.0%                                               (x)     Denatured absolute ethyl                                                                         10.0%                                                      alcohol                                                               (xi)    Methyl para-hydroxybenzoate                                                                      0.2%                                                       (preservative)                                                 C:     (xii)   Terephthalylidenedicamfor-                                                                       3.3%                                                       sulfonic acid at a                                                            concentration of 33%                                                          in water                                                              (xiii)  Triethanolamine    0.7%                                                       (neutralizing agent)                                           ______________________________________                                    

Preparation of the phase A₁ +A₂ :

The constituents of A₁ were dissolved at 80° C. When the mixture wasclear, the temperature was decreased to 65° C. and A₂ was added. Themixture was continuously clear and homogeneous. The temperature wasmaintained at 65° C.

Formulation:

The constituents of B were dissolved at 85° C.-90° C. in a beaker. Afterassuring the clarity, the temperature was adjusted to 65° C. Theemulsion was produced, with stirring, by pouring (A₁ +A₂) into B. Thecooling was continued with stirring. At 40° C., phase C was added, againunder stirring, and the mixture was permitted to cool to 20° C. withstirring.

A white care cream was obtained for protecting the skin, on a dailybasis, from the deleterious effects of UV irradiation.

EXAMPLE 3

Gel for daily use and for protecting against sunlight:

    ______________________________________                                        Composition                                                                   ______________________________________                                        A:     (i)     Demineralized water q.s.                                                                       for 100%                                             (ii)    Glycerol         3.0%                                                 (iii)   Methyl para-hydroxybenzoate                                                                    0.2%                                                 (iv)    Dequest 2046     1.0%                                                 (v)     Xanthan gum (thickening                                                                        0.2%                                                         agent)                                                         B:     (vi)    Parsol MCX (UVB screening                                                                      4.0%                                                         agent)                                                                (vii)   Alkyl benzoate (Finsov TN                                                                      4.0%                                                         marketed by Witco)                                                    (viii)  Carbomer (Pemulen TR 2,                                                                        0.5%                                                         marketed by Goodrich)                                                 (ix)    Triethanolamine  0.5%                                          C:     (x)     Terephthalylidenedicamphor-                                                                    2.3%                                                         sulfonic acid at a                                                            concentration of 33% in                                                       water                                                                 (xi)    Triethanolamine (neutralizing                                                                  0.7%                                                         agent)                                                         ______________________________________                                    

Formulation:

Phase A was prepared by sprinkling the gelling agent, with stirring,into the water containing the dissolved ingredients. Emulsification wascarried out, phase B being incorporated into phase A, with stirring. Themixture was rendered smooth and was permitted to cool with slowpaddle-stirring. Phase C was added at 35° C. and the mixture waspermitted to cool to 25° C. with stirring.

EXAMPLE 4

Water-in-oil cream:

    ______________________________________                                        Composition                                                                   ______________________________________                                        A:     (i)     Protegin X (emulsifying                                                                        15.00%                                                       agent)                                                                (ii)    Liquid petrolatum                                                                              4.00%                                                (iii)   Sunflower oil    6.00%                                         B:     (iv)    Water            q.s. for 100%                                        (v)     Glycerol         5.00%                                                (vi)    Iron chelating agent                                                                           2.00%                                                (vii)   Sodium chloride  1.3%                                          C:     (viii)  Terephthalylidenedicamphor-                                                                    6.1%                                                         sulfonic acid at a                                                            concentration of 33% in                                                       water                                                                 (ix)    Triethanolamine (neutralizing                                                                  1.2%                                                         agent)                                                         ______________________________________                                    

EXAMPLE 5

Oil-in-water cream:

    ______________________________________                                        Composition                                                                   ______________________________________                                        A:   (i)     Methylglucose stearate (Glucate SS,                                                               3.00%                                                     Amerchol)                                                             (ii)    Stearic acid        0.7%                                              (iii)   Liquid petrolatum   5.00%                                             (iv)    Isostearyl isostearate                                                                            5.00%                                             (v)     Cyclomethicone      5.00%                                        B:   (vi)    Sucrose stearate    1.3%                                              (vii)   Glycerol            2.00%                                             (viii)  Hexylene glycol     4.00%                                             (ix)    Water               q.s. for 100%                                     (x)     Dequest 2046 (Iron chelating                                                                      2.00%                                                     agent)                                                           C:   (xi)    Terephthalylidenedicamphor-                                                                       2.5%                                                      sulfonic acid at a                                                            concentration of 33% in                                                       water                                                                 (xii)   Triethanolamine (neutralizing                                                                     0.5%                                                      agent)                                                           ______________________________________                                    

While the invention has been described in terms of various preferredembodiments, the skilled artisan will appreciate that variousmodifications, substitutions, omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims, including equivalents thereof.

What is claimed is:
 1. A topically applicable UVA photoprotectivecosmetic/dermatological composition, comprising:an effectivephotoprotecting amount of at least one UVA screening agent substitutedby one sulfonic acid group having formula (I): ##STR9## wherein Y is --Hor --SO₃ H, optionally neutralized; n is equal to 0 or is a numberranging from 1 to 4; and R₁ is at least one linear or branched chainalkyl or alkoxy radical, which may be identical or different, havingfrom 1 to 4 carbon atoms, and an effective UVA photoprotecting-enhancingamount of at least one otherwise non-UVA photoprotecting iron chelatingagent having an association constant with ferrous or ferric ions greaterthan 10² and selected from the group consisting of the salts ofethylenediaminetetramethylenephosphonic acid andethylenediaminetetraacetic acid, citric acid, tartaric acid, phytic acidand salts of these acids and dibenzyldithiocarbamate, in acosmetically/dermatologically acceptable topical vehicle, carrier ordiluent therefor.
 2. The cosmetic/dermatological composition as definedby claim 1, said association constant being greater than 10⁶.
 3. Thecosmetic/dermatological composition as defined by claim 1, said at leastone iron chelating agent comprising a salt ofethylenediaminetetramethylenephosphonic acid.
 4. Thecosmetic/dermatological composition as defined by claim 1, said at leastone iron chelating agent comprising from 0.001% to 5% by weight thereof.5. The cosmetic/dermatological composition as defined by claim 4, saidat least one iron chelating agent comprising from 0.1% to 2% by weightthereof.
 6. The cosmetic/dermatological composition as defined by claim1, said at least one UVA screening agent comprising from 0.01% to 10% byweight thereof.
 7. The cosmetic/dermatological composition as defined byclaim 6, said at least one UVA screening agent comprising from 0.1% to5% by weight thereof.
 8. The cosmetic/dermatological composition asdefined by claim 1, said at least one UVA screening agent comprising asulfo or sulfonate derivative of benzylidenecamphor.
 9. Thecosmetic/dermatological as defined by claim 1, comprising an emulsion, agel, a cream, a lotion, an ointment, a serum, or a dispersion ofspherules.
 10. The cosmetic/dermatological composition as defined byclaim 1, further comprising at least one antioxidant, anti-free radicalagent or combination thereof.
 11. The cosmetic/dermatologicalcomposition as defined by claim 10, said at least one antioxidant,anti-free radical agent or combination thereof comprising an agent forcombating lipoperoxide radicals, a compound for regenerating oxidizedvitamin E, an agent for combating hydroxyl radicals, an agent forcombating singlet oxygen, an agent for combating superoxide radicalanions, or combination thereof.
 12. The cosmetic/dermatologicalcomposition as defined by claim 11, comprising from 0.05% to 5% byweight of an agent for combating lipoperoxide radicals.
 13. Thecosmetic/dermatological compositions as defined by claim 11, comprisingfrom 0.02% to 3% by weight of an agent for combating lipoperoxideradicals.
 14. The cosmetic/dermatological composition as defined byclaim 1, comprising a pentasodium salt ofethylenediaminetetramethylenephosphonic acid and benzene-1,4-acid.
 15. Atreatment for protecting human skin, hair or combination thereof againstthe deleterious effects of UVA irradiation, comprising topicallyapplying thereto an effective amount of the cosmetic/dermatologicalcomposition as defined by claim
 1. 16. A treatment for protecting humanskin, hair or combination thereof against the deleterious effects offree radicals, comprising topically applying thereto an effective amountof the cosmetic/dermatological composition as defined by claim
 1. 17. Atreatment for protecting human skin, hair or combination thereof againstphotoinduced aging, comprising topically applying thereto an effectiveamount of the cosmetic/dermatological composition as defined by claim 1.18. A treatment for protecting human skin against wrinkles, fine linesor both, comprising topically applying thereto an effective amount ofthe cosmetic/dermatological composition as defined by claim
 1. 19. Thecosmetic/dermatological composition as defined by claim 1, wherein thesulfonic acid group of the said at least one UVA screening agent isneutralized.